1. Field of the Invention
The present invention relates to an image processing apparatus, an image forming apparatus, an image processing system, a computer program, and a recording medium recording the computer program and, more specifically, to a technique of controlling output of digital watermark information.
2. Description of the Background Art
Recently, a technique of embedding digital watermark representing a logo or the like of a copyright holder in image data to prevent, for example, unauthorized copying of image data has come to be known.
By way of example, Japanese Patent Laying-Open No. 2000-216982 (hereinafter referred to as “'982 Reference”) discloses a technique of performing bit shift processing only in an area to which a visible digital watermark is to be inserted in a luminance plane taken out from original image after color space conversion, whereby the contents of least significant bit are discarded and the area of most significant bit plane is replaced by a binary image of the visible digital watermark.
Japanese Patent Laying-Open No. 2001-169093 (hereinafter referred to as “'093 Reference”) discloses a technique of compressing part of bit planes of image data representing an original image, replacing the compressed image data with visible digital watermark information, and embedding the compressed image data in the bit plane of the 0-th bit.
Though '982 Reference and '093 Reference disclose techniques for embedding digital watermark information in the image data, these references are silent about the technique of controlling output of the embedded digital watermark information.